1. Field of the Invention
Embodiments of the present invention generally relate to a magnetic read head for use in a hard disk drive.
2. Description of the Related Art
The heart of a computer is a magnetic disk drive which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing, the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
As the areal storage density in hard disk drives (HDDs) increases, the demand for a larger magnetoresistive effect has led to extensive research efforts worldwide. Particularly, a barrier layer-based magnetic tunnel junction (MTJ) is currently being used in HDDs. In typical MTJs, band matching between the barrier layer and the adjacent magnetic layers is the most important factor to obtain high magnetoresistance (MR), which is closely related to the epitaxial relationship between the barrier layer and the adjacent layers. Generally, these adjacent layers are amorphous magnetic layers. As the amorphous magnetic layers are deposited on the barrier layer, an intermixing layer is formed due to the less rigid structure of the barrier layer.
In general, the barrier layer has a textured crystalline structure. In order to obtain high MR ratio in this type of MTJ, an annealing step is necessary to alter the amorphous magnetic layers so they have the same textured crystalline structure as the barrier layer. During fabrication, the crystalline barrier layer and the amorphous magnetic layers tend to intermix, which results in poor device performance.
Therefore, there is a need in the art for less intermixing at the interface between the crystalline barrier layer and the amorphous magnetic layers.